Focus-regulator for electric-arc lamps



(No Moae A W WHEELER 2 sheets-sheet 1.

FOCUS REGULATOR FOR ELBGTRI ARG LAMPS. No. 280,426. Patented July 3, 1883.

N, PETERS, PnnwLnhcgnphnr, wmmnmn ILC.

2 Sheets-Sheet 2.

Patented July 3, 1883.

W. WHEELER.

' Eo'oUs EEGU-LATOE EOE ELEOTEIG AEG LAMPS.

frm/enfer.

N. PETERS. Phom-Lhnagnphgr. washington, uc.

(No Model.)

, UNITED STATES PATENT OFFICE.,-

VILLIAM VHELER, OF CONCORD, MASSACHUSETTS.

FOCUS-REGULATOR FOR ELECTRIC-ARC LAMPS.

SPECIFICATION forming part of Letters Patent No. 280,426, dated July 3, 1883. Application filed March 1881. (No model.)

To a/ZZ whom t 71mg/ concern:

Be it knownl that I, WILLIAM WHEELER, of Concord, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Focusing Lamps; and I do hereby declare the following to be a full and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use it,

reference being had to the accompanying draw! ings, which form part of this specification.

' My invention is especially designed to provide a new or improved method and apparatus for automatically adjusting and maintaining the arc of an electric lamp in a -fixedposition or in any desired focus, whatever be the rates vor the ratio of the consumption of the two carbon pencils of said lamp or the variations thereof.

This invention is also adapted to the like adjustment of the flame of-a candle, or of any' source of artificial light subject to changes of position through the gradual consumption of the light-producing substance. It is especially adapted, however, -for use in electric lamps, to which this speeilication, therefore, particularly refers. The necessity of maintaining the electric light in a fixed position is very evident when it is used in connection with reflectors, lenses, or other optical appliances. It is of material importance in lamps in which the carbons are held by friction rollers or carriers or other devices through which the current passes to said carbons, since by this means the resistance of the current is rendered constant in amount, being determined by the uniform length ofthe carbon between said carrier and the fixed arc. It is also desirable in common electric lamps which are provided with ground or opal glass globes for tempering the dispersion of the light to keep the arc as nearly as possible in the center ofthe globe.

Heretofore the maintenance of the electric are in a fixed position has been attempted in various strictly mechanical devices, by which either the luminous effects are impaired or else the fixation of the are is only approximately effected. Among the rst of those appliances are those lamps in which one of the electrodes (usually the negative one) is so enlarged that its consumption becomes practically mI, such enlargement causing a reduced light production, as well as obstructing its radiation, and those in which the electrodes are placed at an angle with each other, so that the arc is necessarily maintained at their common intersection-a position well known to result in a diminished lighting efficiency. v Among the second class are the majority of the most success-- ful lamps, in which the carbon electrodes of equal ysize are held in the same straight line (usually a vertical one) in carriers so connect ed and actuated that the amount of feed motion imparted to the negative carrier is absolutely xed at some invariable fraction (usually one-half) of that of the positive carrier to compensate for the unequal consumption of the two carbons under the action of a current of constant direction. This position of the carbons is the one most favorable to the economical production of li glit, but the arbitrary meth` od of adjustment is only rudely approximate, since it operates quite independently of the variable ates and ratios o f the consumption of the two carbons, which range from' less than two to one to more than live to one.

By my invention the adjustment and main tenance of the source of light in any desired position is effected by means of certain apparatus whereby the luminous property of the light itself is caused to govern the motions of the materials by means of which said light is produced. Any change of the directions in which light radiates from the source toward a certain fixed part of the apparatus, such as would be caused by the slightest movement of said source from its normal position, directly causes such a movement of the light-producing material as to restore the light to its prescribed position. Hence, since the least error in the position of the light is made the agent for its own correction, the desired result is secured automatically with invariable accuracy, and under any variations in the rate and ratio of consumption of the light-producingmaterial.

Figures 1, 2, and 3 of the aforesaid drawings represent isometric proj ections 5 and Fig. 4, a side elevation of different modifications of this invention, to be fully explained hereinafter.

In Fig. l, A denotes the arc in an electric IOO lamp, of which the parts essential to this description are shown.

B represents a prism or reiieetor iiXed adjustably or otherwise in any convenient position, so as to intercept the beam of light radiating from said arc at about right angles with the line ofthe cai-bons, and to reflect said beam at a right angle, or thereabout, so that it i'alls normally in the open space between, and on the adjoining edges ol a pair ol' selenium eells, commonly so called, (represented at C C and C' O, respectively, and fully described hereinafter.) As shown in Fig. l, each cell is double, consisting, practically, ol' two cells adjoining each other and separated by any non-conducting film. Each section consists of two wires or conductors separated by and embedded in a thin layer of selenium, suitably prepared so as to develop a stat-e ol' allotropy, in which its electrical conductivity is most sensitively ali'ected by light, and formed .into cells, so called, presenting a relatively large extent ol' light-absorbing surface. rlhe said cells are designed to o'ter variable electrical resistances, depending (inversely) upon the amount and intensity of the light falling thereou, and to offer equal resistances under equal` illumination; hence, for the purposes of this invention, they may be defined to bc any cells or devices presenting variable electrical resistance under the effect ot' light and heat, or either of them. Saidcells are excluded as i'ar as possible from the action ot' any other light than that which comes lfrom the arc A through the reflector B.

D represents a small electromotor actuated by a small amount ot' the electric current derived through a suitable shunt, or otherwise, vfrom the main. conductor E E, and passing through the motor conductor F, the two branches thereof, the cells C and C", and the connnutator plates or brushes l and I, in proportions and directions determined by the relative conductivity of said cells, and returit ing to said main conductor through the cells C and C and the conductor F7 subject to the relative conductivity ol' said cells. rlhe said motor D is oi' a well-known form, consisting of a xed U-shaped magnet, between the two opposite poles of which is mounted a revolving armature, around which passes an insulated coil of conducting-wire. The two opposite ends of said coil are jointed to suitable commutators attached to one end of said ar` mature after the usual manner, andthe coil thereby placed in an electric circuit by the contact ol" said commutators with the commutator-brushes I and I', through which connection is made with the conductors F and F. The passage of an electric current through the said motor-that is to say, through said coil around the armature thereof-results in the revolution o1" said arn'iature, caused, as is well known, by the alternate attraction and repulsion taking place between the sides of the armature, together with the coil thereon and the poles of the magnet, the direction ol' such revolution depending upon the direction in which the exciting-current traverses said coil. The motor connects by suitable gearing with thc friction rollers or carriers G and H, through the latter of which the main current is conducted to produce the are. The magnet ol" the motor D is represented in the drawings as of soft iron, inagnetized by the electric current passing through a coil ol' the main conduetor'E E around said magnet. Any part ot' the main current through the arc, or any other current, may be used for either ol" the pur poses specified above, and a permanent nmg net may be substituted in the motor; or any other' suitable motor operated by electricity may be substituted for that shown.

Inasmuch as my invention does not reler to the regulation ol' the distance between the carbons or to regulators specilically so called, but to the focusing or adjustment in lposition of that part of the lamp which controls the position ot' the light simply, hence the lower carbon is represented in the drawings as the one -to be actuated by the said motor.

XVith this construction the operation ol" the combination shown in Fig` l may be thus described: The main circuit passes through the conductor E E, the carrier H, the carbon pencils, the arc A., A certain amount el' the said current, which may be any desired `part, or the whole, it' need be, is shunted and made to pass tid, the conductor F F. Between Fand F two paths or circuits ot' equal but va riable electrical resistances are interposed l'or the passage of said shunted current. Between these two circuits interposing variable electrical resistances the said current divides itself or is divided into two currents, each one ol' which passes through the motor D on a conunon eonductor or coil, above described, but in opposite directions, and in proportions governed by the relative resistanees presented by the double selenium cells (l C and C C". So long as the arc Ais in or nearly in its normal position the beam of light intercepted and reiiected by the prism B l'alls equally upon said cells, which may be of greater or less distance apart, as desired. The y are, then, equal ly illumined, and therefore intel-pose equal resistances to the two divisions of the shunted current; hence the same quantity and iutensity ol' current passes through the motor l) in each of two opposite directions, said currents therefore neutralizing cach other, causing no action ol the motor, and hence leaving the are undisturbed. [It is to bev understood that in this description such terms and l'orms ol' expression arc employed as are admissible in the popular theory regarding electrical currents, and as do not impair the practical signilicanee of this specification] Now, by the gradual consumption of the lower carbon the are descends, whereupon the rellected beam l'alls more upon the double cell C C and less upon the cell C G, and the former becomes a bet- IOO IZO

i @salme whereby said beam sends its rays directly upon one or both ot` the cells of variable resistance. A represents the electric arc in the focus ot' a parabolic reflector, A2, through one side of which, in the horizontal plane ot' said focus, is formed an opening, which is provided or incl osed externally with a suitable case or box, M. The outer end or t'aee of' said ease or box made perpendicular ito the said beam of" light. he appearance ofthe said opening and case upon the inside ofthe reflector is shown f'or convenience in dotted lilies upon the opposite side thereof' at M. The outer f'aee of.' the ease M is provided and fitted with a thin adjustable slide, N, in which is a small opening,through which the exciting or governing beam passes. Said perforated slide il v.is connected with the case M through er by means otthe adj listing-screw O, by means of' which said slide is moved up or down and the direction. of the transmitted beam, together with its relation to the cells (l and (l, moditied thereby. It desirable, the perforated slide N may be provided with a smaller adjustable slide, by which the laperture through the slide N may be diminished or enlarged, and the size of;` the transmitted teain varied in accordance with the size of.l the arc and the cells, the sensitiveness of' the latter to the action of.' the light, e.

It is also to be noticed that in the motor represented in Fig. 3, in combination with the single variable-resistance cells (l and (Y, are two coils, a: y, passing in opposite directions around the magnet itself', instead ot' around the armature, said coils beingin the eireuits ofthe two opposing currents regulated by said eells l and U. Their united currents are then passed through the eommutator plate or brush 1l. and the single eoil of' the ar- .mature o'f' the motor D, af'ter a common f'ashion f'or motors, and rejoined with the main current through the plate .P and conductor F. For the purpose ot' exciting the armature, the main current may be used, if' f'or any reasonsueh as interposing a certain amount ot' rcsistanee between the connections with the conductor F and liv-it should be desirable. \Vhen, now, the arc A. begins to l'all, the outer end otl the exciting` beam of" light. Ypassing through M begins to rise, instantly rendering the cell (l a better conductor and the cell C a poorer one. The major portion of` the current vflowing through the coiuluetor F will thereupon pass through the cell C and the magnet-coil y, nearer thefront and.right-handside ot' the view, thereby causing the motor so to operate as to ett'ect the required adjustment ot' the lower carbon, and hence of' the are A. It, however, the cell (V should become the better conductor bythe upward movement of' the said are, the larger part ofthe current would pass through the said cell l and the magnet-eoil a', nearer the back and left-hand side of' the view, thereby etl'ecting the (amtuary adjustment or movement ot' the are. fn practice, the exciting beam ot1 light, by automatic adjustment,

vpreviously described.

falls constantly upon the cell C more fully than on the cell (Y, to just the extent necessary to cause the carbon pencil or electrode to be moved toward the are at the same rate that it is consumed therein, as previously explained. It will be seen, therefore, that the principal Vf'unction of the secondary cell C and its connccting-eircuit is net to eff'ect the downward or contrary movement ot' the adjustable earbon, but, primarily, to et'fect the counterpoise or neutrality of' resistances, and ot' currents by which the carbon and the motor shall remain unmoved and iixed so long as the are is in its proper position, and, secondarily, to more promptly ef'f'ect the upward limit of' the movement of' the said carbon; also to increase the general sensitiveness ot' the apparatus, as

It is evident, therefore, that the variable-resistance cells (I can be substituted by a coil or cell of' uniform resistance, said` uni f'orm resistance to be less than the maximum resistance oi' the remaining cell of' variable resistance when the latter is the least exposed to the influence of.' the exciting beam ol" light, and. to be greater than the minimum resistance of" said cell ot' variable resistance when the latter most exposed to the influence of' the exciting beam of' light. This invention theref'ore covers the use of' such a cell of' fixed resistance in, substitution f'or one of the cells of. variable resistance in any of' the lforegoing combinations.

Fig. t represents a side elevation of an electric or other lamp fitted. with this invention, in which the prism .I5 is mounted in the vertieal column S or other support of' said lampa l'orm which may be used equally well with or without a reflector. The column S is hol low, and is provided with an opening for the admission of' the cxeiting-lwam at the same heightasthelightsource. lithinsaid column, Vfixed in the adjustable sliding carrier l, is the prism or reflector B, by means of' which the exciting beam of' light is thrown down upon and between the variable-resistanec cells (l and C, which, with the motor and other parts, are inelosed in a chamber beneath the light source, the .lower part of' the column S being enlarged toward the bottom, if' required, to aftordsuf'ficient space f'or the necessary divergence and variation ot' said beam of' light. rlhe carrier R, holding the prism B, is adjustable by means ot' the thumb-screw T, connected therewith and with the top ot' the column or support S. The adjustment of' the said carrier and prism may be better ettected in certain eases by causing them to slide laterally in the line of the beam of' light received by said. prism in suitable ways formed in or upon said column .lt is apparent that with any of' the forego ing combinations, by inserting a candle or other light-producing device in the lower earrier or holder and providing only the motorcurrent described with the necessary circuiteonneetions, the apparatus described becomes a simple light-focusing device adapted f'or use with alight f'rom any artificial source suscepti- I OO ble of such adjustment of position. Therefore I do not wish to confine myself to the use of an electric lamp as shown in the drawings; but any other lamp or artificial light source can be used With equal results.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In combination with devices for producing a beam of light or heat rays, two or more cells or devices, each of variable electrical resistance, depending 'upon the extent or nature of its exposure to the said rays, substantially as described, fixed in and constituting parts of the parallel branches of a divided electrical circuit, substantially as set forth.

2. In combination with apparatus for producing a beam of light and heat, two cells or devices, substantially as described, interposing in two parallel electrical circuits combined therewith variable ratios of their respective re sistances under the variable influences of said beam, substantially as set forth.

3. In combination with a device for producing a beam of light or heat, a cell or device of variable electrical resistance, depending upon its exposure to said beam, constituting a part of one branch of a divided electrical circuit,

and a device of fixed electrical resistance constituting a part of another branch of the same circuit, substantially as set forth.

4. In combination with means for producing a beam of light or heat, two pairs of cells or devices, each pair of variable electrical resistance, according to its exposure to said beam, said pairs being so placed as to be oppositely affected by any operative change in their ex? posure to said beam, and combined with each' other in such manner that the first cell of each pair is directly connected with one pole of an electric circuit, the second cell of each pair directly connected with the other pole of the circuit, each -cell of each pair directly connected with both cells of the other pair, and the two cells of either pair joined with each other through an electric motor operating in combination with said cells, all substantially as set forth.

5. In combination with means for producing and directing a beam of light or heat, the cells or devices C C', having parallel circuitconnections through the motor D, substantially as set forth.

6. In combination with apparatus for producing a beam of light and heat, or either of them, the case M, perforated slide N, and cells C C, all being substantially as set forth.

7. In an electric lamp, the combination of a reiiector, A2, having an opening, and case M, the perforated slide N, adj ustingscrew O, cells C C', electromotor D, and carbon-holders, snbstantially as set forth.

8. In an electric lamp, in combination with theL column or support S, the prism B, cells C C', an adj Listing-motor, substantially as set forth.

9. In an electric lamp, in combination with .the column S, the prism B, holder B, adjust ing-screw T, and cells C C, substantially as set forth.

VILLIAM VHEELER.

Witnesses: v

R. H. EDDY,

E. B. PRATT. 

